Basically, such a device is known from DE-AS 23 19 060 and from the company brochure "HURTH Walzgratwerkzeuge" (HURTH Generating Burr Tools). Forming on gears made by a cutting process, on the tooth end edges, is a burr that needs to be removed for various reasons. Such burr is troublesome, since in the subsequent operations a flat face, for example the end face of the gear, frequently is meant to serve as clamping and reference surface.
A particular risk to the teeth is a hardened burr, which at the latest will come off as the gears run in the transmission and can damage the tooth flanks. Apart from that, a burr left behind represents also an injury hazard in handling the work. Therefore, numerous burr removal methods and apparatuses have been in use for a long time. Removing just the burrs, however, is mostly insufficient. Hardening, for example, involves the risk that the pointed edge becomes as hard as glass, due to excess carburization, and then breaks off under load. Therefore, the tooth end edge must additionally be provided with a chamfer; the latter also protects the active tooth surface from damage. This objective is accomplished with the categorical apparatus, in that work material at the edge is displaced between the tooth flank and the end face so as to produce a single-flank or dual-flank chamfer. The work material is in this plastic deformation displaced by the deburring wheel toward the end face, creating a so-called secondary burr. This secondary burr is removed with a cutter. Termed secondary burr cutter, this cutter is known in various embodiments and may be configured, e.g., as a rotatable disk.
In the prior systems the work is machined wet using a cutting oil or cutting emulsion. This fluid not only contributes to machining the work, by reducing the friction, but serves also the removal of the accruing chips. Using such cutting fluid, however, is associated with several disadvantages. Following the deburring, the work is hardened, wherein cutting oil residues represent a hindrance. Besides, cutting oil is relatively expensive. But high costs are caused not only by its procurement, but also by the disposal of the spent cutting oil, that is, of the steel chips saturated with cutting oil. Therefore, there is a need for a deburring system that is able to operate without the use of cutting fluid. This need went unsatisfied so far, because the chips produced in deburring scatter around uncontrolled, due to the absence of a cutting fluid in the system, and result in disturbances. For example, the chips may proceed between the guide gear and the work and may be rolled into the latter, which is extremely disturbing. A further problem in dry deburring is the specific chip removal from the working area. While in wet machining the draining cutting fluid carries the chips along, dry machining involves the risk that the chips, scattering uncontrolled, will accumulate and form undesirable pockets that may impair the operation.
Therefore, the objective underlying the invention is to improve the categorical apparatus to the effect that dry machining of the work is possible. This objective is satisfied according to the invention in that the bed is on the tooling end rearwardly inclined approximately 45.degree. in the direction of tool rotation, in that the slide allows down infeed toward the clamping fixture, in that the secondary burr disk meshes with the upper area of the work, in that a front wall opposing the bed is provided in the working area, said wall being forwardly inclined about 45.degree. opposite to the direction of tool rotation, creating a chip hopper of about 90.degree., and in that the guide gear has in its center a peripheral groove.
The inclined arrangement of the bed in the direction of tool rotation, and thus also in the direction of rotation of the secondary burr disk, achieves that the accruing chips will not proceed between the work and the guide gear, but will be deflected down from the work area into the hopper formed by the bed and the as well inclined front wall. In the event that chips created in deburring should nonetheless proceed between the work and guide gear, the center peripheral groove of the guide gear prevents the chips from being rolled into the tooth flanks of the work.
To further reduce the risk of chip penetration between the guide gear and the work, the secondary burr disk has an outwardly inclined peripheral edge. This achieves a sideways deflection of the chips formed.
Since dry deburring produces very small particles that may deposit on the guide gear and the dressing wheel, an improvement of the invention is characterized by a rotating brush able to engage the tool when the slide is in its upper position of rest, away from the work.
In view of the possible deposition of small particles on the tool, a further provision is coating the guide gear and the deburring wheel with a material reducing friction.
To prevent dry chips from clinging to the walls of the apparatus, its interior is lined with stainless steel panels of low intrinsic magnetism.
A favorable improvement of the invention is characterized by a lift mechanism enabling the superimposition of a lift motion on the radial infeed motion of the tool. This makes possible a defined increase of the axial spacing of work and tool prior to infeeding the secondary burr disk, excluding practically entirely the possibility that chips may be rolled into the tooth flanks of the work by the guide gear.
An exemplary embodiment of the apparatus is illustrated in the drawing and more fully explained hereafter.